Fuel control for externally ignited internal combustion engines

ABSTRACT

A fuel control for externally ignited internal combustion engines, including a movable spatial ballistic cam dependent, in a first instance, on engine rotational speed, movements of which being adapted to be transmitted to a fuel calibrating installation, and with the spatial ballistic cam being displaceable along its longitudinal axis. The spatial ballistic cam is displaceable, in second dependence, pursuant to the difference of the operative pressure of the engine combustion air present in the zones upstream and downstream of the throttle valve, so as to rotate the spatial ballistic cam about its longitudinal axis.

United States Patent 1191 Chattopadhayay et al. 0

[ Nov. 26, 1974 FUEL CONTROL FOR EXTERNALLY IGNITED INTERNAL COMBUSTION ENGINES [75] Inventors: Asoke Chattopadhayay, Norf;

Hans-Jiirgen Mtiller, Gelsenkirchen, both of Germany [73] Assignee: Deutsche Vergaser GmbH & Co.

221 Filed: June 14,1973

21 Appl. No.: 370,058

[30] Foreign Application Priority Data June 19, 1972 Germany 2229619 [52] US. Cl 123/140 CC, 123/140 A, 123/140 MP, 123/139 56 [51] Int. Cl. F02d 1/04, F02d l/O6 [58] Field ofS earch 123/140 CC, 140 MP, 140 MC [56] References Cited UNITED STATES PATENTS l/l959 Aldridge 123/140 MP l/l960 Stoltman 123/140 MP 3,064,636 11/1962 Dahl 123/140 MP 3,757,796 9 1973 Boue 123 140 MP FOREIGN PATENTS OR APPLICATIONS 16,309 1/1956 Germany 123/140 cc 1,202,171 2/1958 France. 123 140 cc Primary ExaminerCharles J. Myhre Assistant ExaminerRonald B. Cox

Attorney, Agent, or Firm-Waters, Roditi, Schwartz 8L Nissen [5 7] ABSTRACT A fuel control for externally ignited internal combustion engines, including a movable spatial ballistic cam dependent, in a first instance, on engine rotational speed, movements of which being adapted to be transmitted to a fuel calibrating installation,'and with the spatial ballistic cam being displaceable along its longitudinal axis. The spatial ballistic cam is displaceable, in second dependence, pursuant to the difference of the operative pressure of the engine combustion air present in the zones upstream and downstream of the throttle valve, so as to rotate the spatial ballistic cam about its longitudinal axis.

3 Claims, 1 Drawing Figure FUEL CONTROL FOR EXTERNALLY IGNITED I INTERNAL COMBUSTION ENGINES FIELD OF THE INVENTION The present invention relates to a fuel control for externally ignited internal combustion engines, including a movable spatial ballistic cam dependent, in a first instance, on engine rotational speed, movements of which being adapted to be transmitted to a fuel calibrating installation, and with the spatial ballistic cam being displaceable along its longitudinal axis.

DISCUSSION OF THE PRIOR ART A disclosure and various illustrative embodiments of a fuel control of this type have been published in German Petty Pat. No. 1,858,807. The spatial ballistic cams of that type of prior art fuel control are, in a secondary dependence, displaceable in pursuance to the position of the throttle valve for the engine combustion air, so as to rotate the spatial ballistic cams about their longitudinal axes.

The prior art fuel controls possess the disadvantage that they are not suited to be manufactured in mass production, since minor differences in the throttle valve position under one and the same load condition are experienced from engine to engine, in view of which the fuel calibration or dosage cannot be correlated in the best possible or optimum mixture relationship with respect to the input or dosage of air. Furthermore, a long-term use sedimentation deposits on the throttle valve cause cummulative detrimental changes in the fuel-air mixture relationship. Additionally, it is not readily possible to compensate for the various manufacturing tolerances, which also adversely affect the fuel-air mixture relationship.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a novel and improved fuel control which is particularly suited for manufacture through mass production, and in which the spatial ballistic cam is displaceable not in dependence upon the position of the throttle valve, but rather in conformance with the engine or machine load, and in which there may -concurrently be provided a temperature compensation for engine running-up, and a transition corrector for engine load changes.

In accordance with the present invention this task is inventively solved in that the spatial ballistic cam is displaceable, in second dependence, pursuant to the difference of the operative pressure of the engine combustion air present in the zones upstream and downstream of the throttle valve, so as to rotate the spatial ballistic cam about its longitudinal axis.

The pressure differential may be directly regulated by means of a valve which is dependent upon the machine temperature so as tocontrol a bypass channel circumventing the throttle valve. In that manner, temperature compensation is obtained for the running-up of the internal combustion engine.

Advantageously, the pressure difierential, by means of a suitable conduit, is operatively effective on a pneumatic servomotor which has movable elements in an operative connection with the spatial ballistic cam. Within the conduit there may be incorporated an adjustable throttling component having the purpose of providing a transition corrector for-the engine load changes. I

The advantage of the invention lies particularly in that the manufacturing tolerances of the throttle valve itself, its internal components and mechanical transmission elements do not exert any effect on the fuel calibration or dosage. Also, aged or long-term sedimentation deposits on the throttle valve no longer affect the fuel dosage. According to the invention, the fuel calibration or dosage is now advantageously only dependent on the pressure differential and thereby on the volumetric flow of the engine combustion air. A further advantage lies in the ready correctability of the fuel calibration or dosage during load changes and temperature variations.

BRIEF DESCRIPTION OF THE DRAWING Reference may now be had to the single FIGURE of the drawing showing a preferred illustrative embodiment of a fuel control according to the present invention.

DETAILED DESCRIPTION Referring now in more particular detail to the drawing, an air inlet passageway 1 of an internal combustion engine has combustion air flowing therethrough in the direction of the illustrated arrow. An air filter 2 is located at the inlet end of the air inlet passageway. Within the air inlet passageway 1 there is located a throttle valve 3 which may be actuated, as required, by means of an actuating lever 4. Formed in the wall of the air inlet passageway 1 is a bypass channel 5 which circumvents throttle valve 3. The free flow cross-section of the bypass channel 5 may be regulated by a thermostatic regulating valve 6, through which flows the cooling medium for the internal combustion engine, in the direction of the illustrated arrows.

A conduit 7 leads from a chamber 13, located downstream of throttle valve 3 in the passageway 1, through an adjustable valve element 8 into a first control pressure chamber 9 of a pneumatic servomotor 10. A second control. pressure chamber 11 of the servomotor 10 communicates with the atmosphere. However, the second control pressure chamber 11 may also be connected, as shown by chain-dotted circuit 12, with a chamber 14 in the air inlet passageway 1 which is located upstream of the throttle valve 3.

A movable piston 15 of the servomotor 10, having a piston rod 16 fastened thereto, forms an operative connection through a driving rod 17 with a crank 19, the Iatter of which is mounted on a shaft 18 so as to be longitudinally adjustable relative thereto by means of a. splined or grooved connection.

A spatial ballistic cam 20 is mounted on the shaft 18 The shaft 18 is supported in a manner so as to be rotatable and axially displaceable. The supports for the shaft 18 are not illustrated.

A sensing lever 21 which has a sensing or contact roller 22 mounted on one thereof, is biased toward the surface of the spatial ballistic cam 20 by the action of a suitable spring (not shown), so as to maintain the contact roller 22 in constant contact with the surface of the spatial ballistic cam. The sensing lever 21 is operatively connected with a rotary slide valve 23, the latter of which regulates the flow of fuel to the internal combustion engine. The fuel enters the rotary slide valve 23 under constant pressure through a conduit 24. Subse- 3. quently, the fuel exits from the rotary slide valve through a dosing or calibrating conduit 25.

During operation the piston 15 is displaced from its at rest position in conformance with the extent of the pressure differential. Thereby, due to its operative connection, the spatial ballistic cam 20 is rotated about its longitudinal axis. If, upon laod variation, there occurs a sudden change in the differential pressure, the damping of the throttling element 8 becomes effective so as to compensate for fuel dosing errors and control oscillations.

The bypass passageway is increasingly throttled the lower the machine or engine temperature. Conditionally through the interrelated increase in the differential pressure, there is obtained an enriched fuel-air mixture upon starting and during the running-up of the internal combustion engine.

The invention is not limited to the described exemplary embodiment, and various modifications may be ascertainable within the scope of the appended claims.

What is claimed is:

1. Fuel control for externally ignited internal combustion engines, comprising; a movable spatial ballistic cam responsive,in a first instance, to engine rotational speed; fuel dosage means adapted to have movements of said cam communicated thereto, said cam being displaceable along its longitudinal axis; a throttle valve; means for rotating said cam about its longitudinal axis, in a second instance, dependent upon a differential pressure of the combustion air for said engines upstream and downstream of said throttle valve; a bypass passageway circumventing said throttle valve; and valve means in said passageway for directly regulating the pressure differential in dependence upon the tem perature of said engine.

2. Fuel control as claimed in claim 1, comprising a pneumatic servomotor; and conduit means communicating said pressure differential to said servomotor, said servomotor having movable portions operatively connected to said spatial ballistic cam so as to actuate the latter in response to said pressure differentialv 3. Fuel control as claimed in claim 2, comprising an adjustable valve element being positioned in said conduit means. 

1. Fuel control for externally ignited internal combustion engines, comprising; a movable spatial ballistic cam responsive, in a first instance, to engine rotational speed; fuel dosage means adapted to have movements of said cam communicated thereto, said cam being displaceable along its longitudinal axis; a throttle valve; means for rotating said cam about its longitudinal axis, in a second instance, dependent upon a differential pressure of the combustion air for said engines upstream and downstream of said throttle valve; a bypass passageway circumventing said throttle valve; and valve means in said passageway for directly regulating the pressure differential in dependence upon the temperature of said engine.
 2. Fuel control as claimed in claim 1, comprising a pneumatic servomotor; and conduit means communicating said pressure differential to said servomotor, said servomotor having movable portions operatively connected to said spatial ballistic cam so as to actuate the latter in response to said pressure differential.
 3. Fuel control as claimed in claim 2, comprising an adjustable valve element being positioned in said conduit means. 